Copy Textbox Content To Cell

I want to use a Login screen for a little "request-program" I made. Logging in works and when I log in as an administrator, an extra window pops up where I can add and remove new users (with pass). Users (column A) and passwords (column B) are located in a 'logins'-tab in my worksheet. Adding a new username works fine, but I don't seem to get the password next to the username. When adding a new name, the code searches for a blank cell in column A, adds the name and then sort the rows (so username and password still correspond). Usernames are filled out in a combobox (so you can select one to delete) and passwords in a textbox.